Serial Bus Bit Time Adaptation for EMC Compliance
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Solution Overview
Problem
Current serial bus systems, such as CAN FD, face limitations in achieving high data rates while maintaining error robustness due to constraints on edge steepness and voltage differences, which affect data transfer efficiency and electromagnetic compatibility.
Innovation Solution
A communication control device for user stations in serial bus systems that adapts bit time as a function of edge height between bits, allowing for increased data transfer rates without compromising error robustness, by using a bit time modifier module and voltage association module to optimize signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the edge steepness of the signal is increased to achieve higher data rates, then the data transfer rate is improved, but the electromagnetic radiation increases and exceeds EMC limiting values
Solution Approach 1:
The patent changes the temporal parameter (bit time duration) instead of the electrical parameter (edge steepness). By extending the bit time for bits with large voltage differences, the system achieves reliable signal differentiation without increasing electromagnetic radiation, thus resolving the contradiction between data rate and EMC compliance
2Reliability
If the voltage differences between bus states are increased to improve signal differentiation, then the reliability of bit detection is improved, but the transient effect duration increases and reduces the net data rate
Solution Approach 1:
The patent introduces dynamic bit time adaptation where the bit time duration varies depending on the voltage difference of each bit. Bits with larger voltage differences are assigned longer bit times to allow complete transient effects, while bits with smaller voltage differences use shorter bit times. This dynamic adjustment maintains reliable detection while maximizing overall data throughput
3Reliability
If the bit time is extended to accommodate transient effects from large voltage differences, then the error robustness is improved, but the data transfer rate decreases
Solution Approach 1:
The patent applies different bit time durations to different bits based on their local characteristics (voltage differences). Instead of uniformly extending all bit times, only bits with large voltage differences that cause significant transient effects receive extended bit times. This localized adaptation ensures error robustness where needed while maintaining high data rates for other bits
Data Source
AI summary
A communication control device for a user station for a serial bus system and a method for communicating in a serial bus system. The communication control device controls a communication of the user station with at least one other user station of the bus system, and to generate a transmission signal for transmission onto a bus of the bus system and/or to receive a signal from the bus. The communication control device is designed to generate the transmission signal according to a frame. The communication control device is designed to generate the transmission signal in such a way that in the transmission signal, the bit time of at least one bit is adapted as a function of an edge height that is to be provided between the at least one bit and the preceding bit in a signal in which the bit is to be transferred via the bus.